Method of repairing heat cracks on ferrous metal engines



A. J. RISCKY June 17, 1969 METHOD OF REPAIRING HEAT CRACKS ON FERROUS METAL ENGINES riginal Filed Au 15, 1966 INVENT OR azmrJ/iacy BY A'ITORNEYS United States Patent 3,450,575 METHOD OF REPAIRING HEAT CRA'CKS 0N FERROUS METAL ENGINES Alexander J. Riscky, 6220 Longhorn Trail, Fort Worth, Tex. 76135 Continuation of application Ser. No. 572,582, Aug. 15, 1966. This application Jan. 17, 1968, Ser. No. 729,829

Int. Cl. B231) 7/04; C01b 21/38 US. Cl. 1486.14 6 Claims ABSTRACT OF THE DISCLOSURE Following are disclosed methods and solutions for repairing heat cracks of the type frequently found in valve seats in internal combustion engines by application of nitric acid or nitric acid and hydrogen peroxide.

CROSS REFERENCE TO RELATED APPLICATION This is a continuation of an application entitled Engine Repair Means, Ser. No. 572,582, filed Aug. 15, 1966, now abandoned.

Frequently, internal combustion engines in automotive vehicles, for example, may become overheated due to loss of Water, generally caused by equipment malfunction such as damaged water pumps. The metal of an engine block or cylinder head is often damaged when its temperature increases to a certain level. At high temperatures, small cracks may form in the metal of internal combustion engines, especially near or across the valve seats. An exhaust valve seat in particular is a region in which small heat cracks often form, since the temperature of the metal here is generally higher than that of other regions such as the intake valve region.

Although heat cracks in internal combustion engines may be extremely small, measuring at times only two or three thousandths of an inch wide, they frequently extend through the thickness of the metal and into the water jacket which surrounds the associated head or block. Water often enters the cylinder through these heat cracks, especially during the suction stroke to form droplets around the spark plug, causing it to misfire. This detrimental result is particularly common on engines that have valve-in head arrangements.

Presently available methods for repairing these cracks are so expensive that frequently it is more economical to buy a new cylinder head rather than repair one. This problem is more diflicult than the one encountered when an engine block is damaged by freezing of the water during winter. The large cracks caused by freezing water may frequently be repaired by brazing, for example. But the heat cracks described above may not be ordinarily brazed, and the repair problem is the more difficult of the two.

I have discovered that heat cracks in internal combustion engines may be repaired in a surprising manner. By applying a chemical solution to these cracks with an eye dropper or similar instrument, they may be permanently sealed to effectively prevent entrance of water from the water jacket. The solution I originated for this purpose does not fill the heat cracks in the manner of an adhesive or sealing compound, but apparently reacts with the elements of the metal or metal alloy to form a new composition that bridges the cracks.

It is, accordingly, the general object of my invention to provide improved means for repairing heat cracks that develop in metal structures such as internal combustion engines.

Another object of my invention is to provide a method for repairing heat cracks to effectively prevent entrance of water from the water jacket into the cylinder.

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Another object of my invention is to provide a composition or solution which may be applied to the heat cracks that frequently develop in internal combustion engines, especially in the region of the valve seats, when engines become overheated.

These and other objects are effected by my invention as will be apparent from the following description taken in accordance with the accompanying drawing, forming a part of this application, in which:

The figure in the drawing is a fragmentary perspective view of the cylinder head of an overhead valve engine having a heat crack extending across one exhaust valve seat.

The numeral 11 designates in general a cylinder head having a cavity 13 which forms a portion of the combustion chamber. An intake valve 15 is supported in the cylinder head 11 and engages a seat (not shown) machined in one region of the metal forming cavity 13. An exhaust valve (not shown) is carried by the cylinder head and has a conical surface adapted to engage the valve seat 17. Further, cylinder head 11 has a machined planar surface 19 that engages a mating surface of an engine block (not shown). Threaded apertures 21 are utilized to secure cylinder head 11 to the engine block. A plurality of apertures 23 may be seen intersecting planar surface 19 and these apertures define passages for the flow of cooling water between the water jacket of the cylinder head and the engine block. A spark plug 25 may be seen extending through the cylinder head with electrodes (not shown) exposed inside cavity 13.

The particular cylinder head illustrated in FIG. 1 has been overheated to the extent that a heat crack 27 has formed in the region of the exhaust valve and extends from exhaust valve seat 17 toward intake valve 15. Depending upon the extent of the engine overheating, the heat crack 27 may have extended completely through the cross section of the metal to form a passageway to the water jacket thereof. In some instances the heat crack 27 may extend into communication with the valve seat (not shown) of intake valve 15.

To repair the heat crack 27 shown in FIG. 1, I first cleanse the region around the heat crack with a suitable cleaning composition such as gasoline to remove foreign particles such as carbon. Next I prepare a solution of nitric acid and hydrogen peroxide. I have discovered that a mixture of nitric acid and hydrogen peroxide, if applied to the heat crack by suitable means such as by an eye dropper or a solid implement such as a toothpick, reacts with the metal of the cylinder head to effectively seal the crack. After the solution has been given a period of five to ten minutes to react completely with the metal of the cylinder head, I then grind the valve seat 17 in the usual manner to provide a finished surface. Cylinder heads or engine blocks repaired in this manner operate essentially as if new. Water no longer seeps through the heat cracks into the combustion chambers to foul the electrodes of the spark plugs. Thus, it is no longer necessary to utilize expensive methods for repairing heat cracks in internal combustion engines, nor is it ordinarily necessary to purchase new cylinder heads.

For effective repair the hydrogen peroxide and nitric acid should be mixed in the following proportions:

Assuming the use of a 3% solution of hydrogen peroxide, one part by volume should be mixed with from 15 to 25 parts by volume of fuming nitric acid meeting ACS specifications. For best results, one part by volume of a 3% solution of hydrogen peroxide should be mixed with 20 parts by volume of nitric acid. The particular ratios of the above constituents must be adjusted according to the concentrations of the solution if concentrations other than those specified above are used. However, a 3% solution of hydrogen peroxide is conveniently available as is nitric acid provided in accordance with ACS specifications.

While I cannot be certain why the above solution is so effective in repairing the heat cracks in internal combustion engines, possibly ferrous nitrides or, specifically, ferric nitrates are formed in the heat cracks in accordance with the following formula:

It is possible, however, that ferrosoferric oxide, known in nature as the mineral magnetite, is formed in accordance with the following formulas:

Whatever may be the correct explanation of the manner in which the above solutions operate, they have been used to repair engines effectively and advantageously.

While a solution of nitric acid and hydrogen peroxide is exceptionally efiective in repairing heat cracks as described above, I have further discovered that nitric acid may be used alone to repair many heat cracks such as those found in automobile engines, although it is not as fast as when using a hydrogen peroxide-nitric acid solution. Additional time and repeated applications are frequently required when only nitric acid is used, both of which depend upon the size of the heat crack and the concentration of the nitric acid. Fuming nitric acid works best in most instances and may be used to repair heat cracks with only one application, although the time required for effective scaling is often increased as compared with the use of a solution of hydrogen peroxide and nitric acid. However, the concentration of nitric acid is not critical but relates to the amount of time required to seal a crack. Concentrations weaker than fuming nitric acid may be used, especially in instances where the cracked engine component is submersed in a bath of nitric acid. Such procedures require significantly increased time to complete the treatment, whereas the use of fuming nitric acid and especially the hydrogen peroxide-nitric acid solution decreases time required to only a few seconds and usually only one application.

I claim:

1. The method of repairing heat cracks in ferrous metal engine cylinder heads or blocks, said method comprising 2. The method defined by claim 1 wherein the relative percentages of the above two ingredients are proportioned substantially from the following:

Parts by volume H202 HNO3 20 3. A solution used for repairing heat cracks in ferrous metal engine cylinder heads or blocks, said solution consisting essentially of one part by volume of hydrogen peroxide (3% solution) and fuming nitric acid (ACS specifications) in a quantity selected from a range varying from 15 to 25 parts by volume.

4. The solution defined by claim 3 wherein the quantity of nitric acid is substantially 20 parts by volume.

5. The method of repairing heat cracks in ferrous metal engine cylinder heads or blocks, especially in the valve seat regions, said method comprising cleansing the heat crack and the region therearound, introducing to the heat crack a solution consisting essentially of nitric acid of a given concentration and subjecting the metal adjacent said heat crack to a reaction with said nitric acid of said given concentration for a period of time sufficient to effect closure of said crack equivalent to a unitary application of fuming nitric acid.

6. The method defined by claim 5 wherein said solution consists essentially of fuming nitric acid.

References Cited UNITED STATES PATENTS 2,301,513 11/1942 Brewer. 2,500,678 3/1950 Hassan. 2,856,275 10/1958 Otto 1486.14 X 2,876,144 3/1959 Bomberger 252-101 X RALPH S. KENDALL, Primary Examiner.

US. Cl. X.R 

